Blade



Sept. 5, 1944. M. e. BOERGER BLADE Filed Aug. 21, 1942 Patented Sept. 5, 1944 BLADE Martin G. Boerger, Racine, Wis., assignor, by

mesne assignments, to Twin Disc Clutch Company, Racine, Wis, a corporation of Wisconsin Application August 21, .1942, Serial No. 455,552

9 Claims.

My invention relates to blades for power units of the prime mover and transmission types such as steam and hydraulic turbines, and hydraulic couplings and hydraulic torque converters.

By way of example, my invention will be described in connection with blades for torque converters. Heretoiore, it has been common practice to make these blades from drawn brass stock which is cut in lengths equal to the length of the finished blades plus the supportin trunnions, the latter being then turned to the proper diameter. The transverse sectional profile of these blades varies from comparatively simple shapes to those having complex curvatures which are designed for maximum efficiency. The

manufacture of the latter in particular requires special machine equipment, which means high unit costs, and the problem becomes more complicated and more expensive with blades of larger size. Moreover, in blades of this character, there is a weight problem involved due to the soiid nature of the part and the latter aspect is further reflected in high material cost owing to the character of the metal.

As a solution of the above problem, there is disclosed and claimed in United States Letters Patent No. 2,293,768, dated August 25, 1942, a hollow blade formed from a stamping and having extending therethrough a trunnion pin whereby the blade is mounted in a rotor. In this construction, tongues are bent out of one of the blade walls interiorly of the blade and serve as locating elements for the trunnion while being secured, as by brazing, to the blade.

The principal object of the present invention is to devise a new arrangement for locating the trunnion relative to the blade which obviates the bending of tongues from the blade wall as indicated above.

A further object is to provide a blade in which the blade thickness is not greater than the diameter of the projecting end of the trunnion.

These and further objects of my invention which are generally similar to those set forth in the above noted patent will be outlined in the following specification, reference being had to the accompanying drawing, and the novel means by which said objects are eflectuated will be definitely pointed out in the claims.

In the drawing:

Fig. 1 is an elevation of my improved blade.

Fig. 2 is an end view of the blade shown in Fig. 1.

Fig. 3 is a side view of the trunnion pin as viewed in the direction of the arrow 3 in Fig. 1.

Fig. 4 is an end view of the trunnion as viewed in Fig. 3.

Fig. 5 is a view similar to Fig. 2 showing the blade before being shaped to its correct curvature.

Fig. 6 is a plan view of the stamping from which the blade is formed.

Figs. '7 and 8 are fragmentary sections of the blade taken along the lines and 8-8, respectively, in Fig. 1.

Referring to the drawing, the numeral 10 designates my improved blade which is generally in the form of an open-ended shell comprising a pair of opposed, impervious walls II and II, which in the particular shape of blade shown are, respectively, concave and convex. Along one side of the blade, these walls are connected by a curved end wall I3 which constitutes the inlet edge of the blade and at the opposite edges the walls are brought together to form the relatively sharp tip 94. Considering the other edges as the ends of the blade, one of the walls, for example the wall II, is provided with a notch 15 at each end edge which act as deaerating apertures in a manner hereinafter explained. A trunnion pin l6 extends through the blade between and in bearing and secured relation to one or both of the walls II and I2 and beyond both ends of the blade for suitable mounting in a carrier (not shown), as illustrated in Fig. 1, or the pin may only project beyond one end of the blade when used in certain stages of torque convertors and in hydraulic couplings which are not provided with shroud rings. The blade is then carried by a cantilever support. If the dimensions of the blade or the operating conditions require, a second trunnion pin may also be employed and this pin would be spaced from the pin ii.

In order to provide maximum strength in the trunnion pin for any given section of blade, I preferably flatten the bearing sides of the pin, as indicated by the numeral I! in Figs. 2. 3, 4. 7 and 8, along that part which is included between the ends of the blade, or the indicated intermediate portion of the pin may possess an appropriate elliptical cross section or be otherwise deiormed. The bearing surfaces of the trunnion pin are shaped and angularly related to conform to the opposed blade walls along the areas of contact and the width of the flattened portion may be greater than the end diameter of the trunnion. This expedient provides the maximum diameter for the projecting ends of the pin and at the same time facilitates the insertion of the pin between the walls II and I! as hereinafter described. Preferably, the extent of the flattening is such that the thiclmess of the blade through the pin is approximately equal to the end diameter of the pin. The flattening is accomplished in such a way that locating formations or lugs I8 are created at the ends of one of the flattened surfaces which fit into notches IS in the ends of one of the blade walls, these lugs being employed to initially locate the trunnion with respect to the blade and the outer surfaces of the lugs may taper inwardly of the blade as at 20 to conform to the blade curvature.

The body of the blade I is preferably made from a flat steel stamping 2| which, in the case of the blade illustrated in Fig, 1, possesses a rectangular shape and may be made from oiled sheet steel of appropriate guage dependent upon the section of the blade and the forces to which it is subjected. The stamping 2| is cut inwardly along its longitudinal edges to form the notches l5 and i9, after which the stamping is reversely bent intermediate its ends and shaped to the desired profile. In this connection, it will be understood that my invention is not restricted to a blade having the profile illustrated in Fig. 2, since the more generic aspects of the invention are directed to an inexpensive and lightweight blade in which the trunnion pin serves to strengthen the blade section by passing completely through the blade. After the stamping has been bent, its adjacent end edges are flattened cold, or "colned, in order to insure that. when the indicated ends are secured together, the abutting portions of the stamping will be sumciently reduced in thickness to provide the required shape at the tip of the blade.

The trunnion pin 18 is then inserted between the walls II and I2 and, in the case of the blade shown in Fig. l, is positioned endwise so that its ends project beyond the ends of the blade and also so that the lugs l8 fit in the notches IS. The adjacent ends of the reversely bent stamping 2| are then temporarily secured to each other by means of one or more spot welds, generally indicated by the numeral 22 in Fig. l, and the complete assembly is then passed through a hydrogen furnace where the pln I6 is brazed to the walls It and I2 and the ends of the stamping 2| are brazed to each other to form the tip I l.

The foregoing arrangement of parts may be employed with any desired blade profile and for impeller or pump blades, turbine or runner blades, and fixed or reaction blades and for any type of power unit in which power is transmitted by means of the impingement of a fluid medium on a blade, and may also be used for steam turbine blades. In the case of impeller and turbine blades in hydraulic power units which are not completely filled with the working fluid, it is necessary to provide some means for insuring a complete deaeration of the interior of the blades, otherwise the rotor to which the blades are secured may be unbalanced during rotation. This result is achieved by the use of the deaerating notches W. In this connection, it will be understood that while blades of this character are more or less snugly fitted between the opposite walls of the carrier, dimensional discrepancies may result in small openings between the edges of some of the blades and the walls of the carrier and the absence of such openings in other similar locations around the unit. Under these conditions. it will be obvious that, unless deaerating openings were provided, the more snugl iltted blades would retain any air that may have collected therein when the hydraulic power unit is out of service, and this mass of air would not be evacuated when the unit began operation. The provision of the notches it completely obviates any operating difllculties in this respect. The invention is not restricted to placing the notches I! along the edges of the blades, for it is contemplated that these openings, as well as the notches is, may be otherwise located, including intermediate positions in the blade surface, with corresponding locatlons for the lugs I8.

I claim:

1. A blade comprising a pair of opposed walls connected along a pair of their opposite edges, respectively, and otherwise spaced from each other, the working surfaces of the walls being smooth and substantially unbroken, and a trunnion pin extending between the walls and secured to at least one wall and having formations fltting into notches in one of the walls for positioning the pin relative to the blade.

2. A blade comprising a one-piece, hollow shell whose opposite walls are shaped to the desired profile and whose outer surface is smooth and substantially unbroken, and a cylindrical trunnion pin extending between the walls and beyond an end 0! the shell for mounting in a carrier, the pin being secured to and bearing on the walls and being flattened along the bearing surfaces to secure maximum diameter of the projecting end of the trunnion and having formations fitting into notches extending for a limited distance inwardly from the end edges of one of the walls for positloning the pin relative to the shell.

3. A blade comprising a pair of opposed walla connected along a pair of their opposite edges. respectively, and otherwise spaced from each other, the working surfaces of the walls being smooth and substantially unbroken, one of the walls having notches extending inwardly for a limited distance from its spaced edges, and a trunnion pin extending between the walls and secured to at least one wall and having formations fitting into the notches for positioning the pin relative to the blade.

4. A blade comprising a pair of opposed walls connected along a pair of their opposite edges, respectively, and otherwise spaced from each other, the working surfaces of the walls being smooth and substantially unbroken, one of the walls having notches extending inwardly for a limited distance from its spaced edges, and a cylindrical trunnion pin extending between the walls and beyond an end of the blade for mounting in a carrier, the pin being secured to and hearing on the walls and being flattened along the bearing surfaces to secure maximum diameter of the projecting end of the trunnion and having formations fitting into the notches for positioning the pin relative to the blade.

5. A blade comprising a. pair 01' opposed walls connected along a pair of their opposite edges, respectively, and otherwise spaced from each other, the working surfaces of the walls being smooth and substantially unbroken, one of the walls having notches extending inwardly for a limited distance from its spaced edges, and a cylindrical trunnion pin extending between the walls and beyond an end of the blade for mounting in a carrier, the pin being secured to and having flattened bearing surfaces abutting the walls between the open ends thereof, the ends of one of the surfaces being reduced in width to thereby create formations which fit into the notches and position the pin relative to the blade.

6. A blade comprising a pair of opposed walls connected along a pair of their opposite edges, respectively, and otherwise spaced from each other, the working surfaces of the walls being smooth and substantially unbroken, from its spaced edges, and a cylindrical trunnion pin extending between the walls and beyond an end of the blade for mounting in a carrier, the pin being secured to and having flattened bearing surfaces abutting the walls between the open ends thereof, one surface at each end being interrupted by a formation fitting into the associated notch for positioning the pin relative to the blade.

7. A blade comprising a pair of opposed walls connected along a pair of their opposite edges, respectively, and otherwise spaced from each other, the working surfaces of the walls being smooth and substantially unbroken, a trunnion pin extending between the walls and secured to at least one wall, and cooperating formations on the pin and a wall adjacent the end edges of said wall for positioning the pin relative to the blade.

8. A blade comprising a pair of opposed walls connected along a pair of their opposite edges,

respectively, and otherwise spaced from each other, and a trunnion pin extending wholly be-- tween the walls and having a cylindrical end projecting beyond an end of the blade for mounting in a carrier, the pin being secured to and bearing on the walls and being flattened along the bearing surfaces and the width of the flattened portion being greater than the end diameter of the pin.

9. A blade comprising a hollow shell whose opposite walls are shaped to the desired profile and whose outer surface is smooth and substantially unbroken, and a trunnion pin extending wholly between the walls and beyond an end of the shell for mounting in a carrier, the pin being secured to and bearing on the walls and being flattened along the bearing surfaces to secure maximum diameter of the projecting end of the trunnion and having formations fitting into notches extending for a limited distance inwardly from the end edges of one of the walls for positioning the pin relative to the shell, the exposed surfaces of the formations tapering inwardly of the blade to conform to the curvature of the shell.

MARTIN G. BOERJGER.

CERTIFICATE OF CORRECTION.

Patent No. 2,557 628.

Septemb er 5, 19th.

MARTIN G. BOERGER'.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring eorrecti on as follows: Page 5, first column, line 7, claim 6, before the word "from" insert --one of the walls having notches extending inwardly for a limited distance--; and that the said Letters Patent should be read with, this correction therein that the same may conform to the record of the ease in the Patent Office,

Signed and sealed this 24th day of October, A. D. 19%.

(Seal) Leslie Frazer Acting Commissioner of Patents.

thereby create formations which fit into the notches and position the pin relative to the blade.

6. A blade comprising a pair of opposed walls connected along a pair of their opposite edges, respectively, and otherwise spaced from each other, the working surfaces of the walls being smooth and substantially unbroken, from its spaced edges, and a cylindrical trunnion pin extending between the walls and beyond an end of the blade for mounting in a carrier, the pin being secured to and having flattened bearing surfaces abutting the walls between the open ends thereof, one surface at each end being interrupted by a formation fitting into the associated notch for positioning the pin relative to the blade.

7. A blade comprising a pair of opposed walls connected along a pair of their opposite edges, respectively, and otherwise spaced from each other, the working surfaces of the walls being smooth and substantially unbroken, a trunnion pin extending between the walls and secured to at least one wall, and cooperating formations on the pin and a wall adjacent the end edges of said wall for positioning the pin relative to the blade.

8. A blade comprising a pair of opposed walls connected along a pair of their opposite edges,

respectively, and otherwise spaced from each other, and a trunnion pin extending wholly be-- tween the walls and having a cylindrical end projecting beyond an end of the blade for mounting in a carrier, the pin being secured to and bearing on the walls and being flattened along the bearing surfaces and the width of the flattened portion being greater than the end diameter of the pin.

9. A blade comprising a hollow shell whose opposite walls are shaped to the desired profile and whose outer surface is smooth and substantially unbroken, and a trunnion pin extending wholly between the walls and beyond an end of the shell for mounting in a carrier, the pin being secured to and bearing on the walls and being flattened along the bearing surfaces to secure maximum diameter of the projecting end of the trunnion and having formations fitting into notches extending for a limited distance inwardly from the end edges of one of the walls for positioning the pin relative to the shell, the exposed surfaces of the formations tapering inwardly of the blade to conform to the curvature of the shell.

MARTIN G. BOERJGER.

CERTIFICATE OF CORRECTION.

Patent No. 2,557 628.

Septemb er 5, 19th.

MARTIN G. BOERGER'.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring eorrecti on as follows: Page 5, first column, line 7, claim 6, before the word "from" insert --one of the walls having notches extending inwardly for a limited distance--; and that the said Letters Patent should be read with, this correction therein that the same may conform to the record of the ease in the Patent Office,

Signed and sealed this 24th day of October, A. D. 19%.

(Seal) Leslie Frazer Acting Commissioner of Patents. 

